@UgokiGyokuyou:
lol you want censorship? Take down all those fanvids/fanfictions and
prevent new ones to be uploaded?

@cks_anime:
Taking Altair stuff down would probably attract too much attention,
but they could make sure that Altair-related content is kept quiet.
Eg have Altair stuff lower down on 'popular <X>' pages than it should
be, and don't let new fanvids/etc show up very high no matter what.
The latter is especially important since we've been told that popular
new fanvids can give Altair new, expanded powers. That's v. dangerous.

Re:Creators has essentially explicitly stated that Creations in
general and Altair in specific derive their power and their abilities
from having an audience see and accept things with the character in them
(manga, games, novels, anime, art, fan works, and so on). Since Altair
is a standalone creation, entirely based on fan-created materials,
she has no 'canon' to shape, define, and limit her the way that other
Creations do; instead, everything comes from fans watching fan-made
videos and art on the in-show equivalents of NicoNico and Pixiv and
making them popular. It's been explicitly stated that some of Altair's
dangerous powers come from secondary fan videos, ones made not by
Altair's initial creator but instead made as goofy bits and pieces by
other fans, then given power by enough people seeing and enjoying them.

It's probably too late to wipe Altair's existing videos and art
from the NicoNico and Pixiv equivalents; fans would probably notice,
there would be a controversy, and you'd cue the Streisand effect, which is exactly
what our protagonists don't want. A similar thing holds about actively
blocking new Altair-related content from appearing at all. However, you
can certainly do things to limit the damage. Visibility and popularity
rankings are generally opaque and reasonably subtle manipulations of
them are unlikely to be noticed and reacted to. So NicoNico and Pixiv
could be coerced to slowly and quietly lower the ranking and prominence
of existing Altair-related content, and especially to manipulate their
systems so that new content would not be seen by a large audience by,
for example, appearing at the top of 'hot new content' pages even if it
normally should.

(New content is especially dangerous because popular new content can
probably give Altair new and expanded powers, in the same way that
secondary fan videos has already given her some that weren't in her
original video source.)

This is not big or loud, and it's not fast, but the characters in
Re:Creators are already playing a relatively long game with a
six-month action plan. They might as well use the government power they
have access to and this time in an attempt not just to build themselves
up but to quietly undercut Altair's base of power, that being her
audience. Every bit helps and they have an uphill struggle.